SSC CGL 2024 Tier-I · 18 September 2024, Shift 3 · General Intelligence and Reasoning · Question 9 of 98

Text as printed on a candidate's response sheet for this shift; answer per SSC's tentative key as marked on that sheet. Solution last reviewed 10 September 2026.

Where this paper and its answers come from

SSC does not publish CGL question papers or a public answer key. The questions and options here are reproduced as printed on a candidate's own response sheet for this shift — the Commission's text, unchanged. Each answer is SSC's tentative key as marked on that sheet; SSC allowed challenges to it and never publishes a final key. The solutions are written by UnlockIAS.

Select the option that represents the letters that when sequentially placed from left to right in the blanks below will complete the letter series. _ _ C _ D C _ _ C C _ _

(a)DDCCCDD
(b)CCDCCDD
(c)DCCCDCC
(d)CDCCDDC

Answer

Why

Correct — D. Rule: C D C repeats — the twelve places are four copies of that unit.

Number the places 1 to 12. The printed letters sit at places 3, 5, 6, 9 and 10 and read C, D, C, C, C.

C D C written out end to end gives

C D C | C D C | C D C | C D C

and every printed letter agrees: place 3 is C, place 5 is D, place 6 is C, places 9 and 10 are C and C.

Now read off the seven blanks in order — places 1, 2, 4, 7, 8, 11, 12 — which give C, D, C, C, D, D, C.

That is CDCCDDC — option (d).

Why the others are wrong

(a)
DDCCCDD — It makes places 1 and 2 read D, D, so the series opens D D C instead of C D C, and it closes on D as well.
(b)
CCDCCDD — Places 1, 2 and 4 come out C, C, D, putting three Cs together at the start. The repeating block never allows more than two Cs in a row.
(c)
DCCCDCC — It starts D, C and ends C, C, C, so neither the opening block nor the closing one is C D C, even though the middle of the series works.

Concept

Solve a blanked letter series from the letters already printed, never by trying the options one by one. Number the twelve places, mark the printed letters, and look for the shortest repeating unit that reproduces all of them.

Here place 3 is C, places 5 and 6 are D and C, and places 9 and 10 are C and C. Test a three-letter unit: its third letter must be C, its second must be D and its first must be C. C D C is the one three-letter unit those five constraints allow.

Then read the answer off the blanks, in blank order. That last step is where a correct pattern still produces the wrong option.

The series uses only C and D, so every option looks plausible at a glance. The discipline that separates them is writing the filled series out in full and checking it against all five printed letters.

Key facts

The series has twelve places and seven blanks, so the option supplying them must carry exactly seven letters.
Printed letters sit at places 3, 5, 6, 9 and 10 and read C, D, C, C, C.
Four repeats of C D C reproduce all five printed letters and leave C, D, C, C, D, D, C for the blanks.

Study next

Numbering the places before filling a blanked letter seriesSeries built on a four-letter repeating block rather than threeChecking a filled series backwards against every printed letter

Common traps

Filling the blanks correctly and then reading them off in the wrong order
Testing the four options in turn instead of finding the block first
Assuming the repeating unit must be two letters long because only C and D appear

The same blank-filling format runs on J and P at 17 Sep 2024, 16:00, Reasoning Q.19, and on F, T and X at 13 Sep 2024, 9:00, Reasoning Q.14.

Related PYQs

No directly related past PYQ was found.